Units for rate constants

[103978133]

What are the units for rate constants in first order, second order and zero order reactions? (As in moles per liter and time in seconds etc.)

[ch1995]

We can figure out the units by knowing that the rate of a reaction will always have the units M/s and the units for concentration ([R]) is M (or mol/L).

0 order:
Rate = k[R]⁰
Rate = k
[M/s] = [M/s]
~ k must have units M/s

1st order:
Rate = k[R]¹
[M/s] = k [M]
~ k must have units 1/s

2nd order:
Rate = k[R]²
[M/s] = k [M]²
~ k must have units 1/Ms